Staple feed



A ril 17, 1962 s. KUFEL, JR., ETAL STAPLE FEED 3 Sheets-Sheet 1 FiledApril 19, 1961 April 1962 s. KUFEL, JR., ETAL 3,029,436

STAPLE FEED.

3 Sheets-Sheet 2 Filed April 19, 1961 April 1962 s. KUFEL, JR., ETAL3,029,436

STAPLE FEED 3 Sheets-Sheet 3 Filed April 19, 1961 United States Patent3,329,436 Patented Apr. 17, 1962 This invention relates to machines forforming and driving staples which are supplied from a flexible strip orroll containing many interconnected staple blanks, for example a stripor roll like the Staple Blank disclosed in Patent No. 2,943,436, issuedJuly 5, 1960, to H. F. Peterssen. More particularly the invention isdirected to an improved mechanism and arrangement for feeding oradvancing a strip of un-formed or partly formed staple blanks tomechanisms which form and drive the staples. Although the invention willbe shown and described in connection with a stapler of the type used inheavy duty industrial work, the principles and structures apply equallyto light duty machine-s such as those designed for desk or oifice use.

A principal object of the invention is to provide a dependable staplefeeding arrangement which is simple, compact and reliable and whichcooperates with the staple forming and driving devices to effecteconomical and rapid operation of the machine.

Another object is to provide a staple feed which opcrates on the firstor leading element in a flexible strip or belt of interconnected stapleelements to pull the stock of staples toward the staple former ordriver. The arrangement of the invention therefore avoids the bucklingand jamming or" staples or blanks in the stapler, which sometimes mayoccur when a strip of staples is fed by a pushing action.

A further object is to provide a staple feeding mechanism with but fewparts, which may be made easily and inexpensively. Still another objectis to provide instrumentalities for holding and guiding the staple stripand individual staples in a dependable fashion during the various stagesof feeding, forming and driving.

These objects are achieved generally by the provision of aspring-pressed plate of unusual design and action, so mounted andarranged that while a staple is being driven by the machine, the platewill engage behind the legs of the following staple as it is beingformed, the plate thereafter pulling the formed staple and the strip ofunformed staple blanks connected therewith toward the driving positionas the staple driver is returned to its starting position and the springpressure on the plate is allowed to act.

Other objects and advantages and details of preferred forms of theinvention will become evident from the following description and theaccompanying drawings forming a part thereof in which:

FIG. 1 is an end view of a stapling head or machine of one type to whichthe invention may be applied, parts being broken away to show interiorconstruction,

FIG. 2 is a side View of the stapler of FIG. 1 with parts indicated insection or broken away,

FIG. 3 is a perspective view of the staple guiding throat, driver andformer of the stapler of FIGS. 1 and 2, as seen looking to the left inFIG. 2,

FIG. 4 is an exploded perspective view showing the staple forming anviland associated staple feeding plate of the invention, as seen looking tothe right in FIG. 2,

FIG. 5 is a sectional view along the line and in the direction of thearrows 5-5 of FIG..2 showing the relationship of the staple guidingthroat, driver and former with respect to the anvil and feeding plate,

FIG. 6 is a combined perspective view showing the end of one kind ofstrip of interconnected staple blanks as used in the stapler, the lastin the series of blanks being partially formed and,a separated fullyformed staple in the approximate position and condition in which it willbe driven,

FIG. 7 is a perspective view similar to FIG. 3 but showing a modifiedform of staple guiding throat, driver and former,

FIG. 8 is a sectional view similar to a portion of FIG. 2 but on asomewhat larger scale showing the parts as they will appear while astaple is being driven but before the following staple is formed,

'FIG. 9 is a view similar to FIG. 8 but showing the parts in thepositions they will occupy while a staple is being formed,

FIG. 10 is a similar view showing the same parts when a first staple hasbeen driven and the second staple has been formed,

FIG. 11 is a similar view showing the parts on the return stroke of thedriver, just before a formed staple is to be fed into the staple guidingthroat, and

FIG. 12 is a vertical sectional view scale through the center of theanvil and top of the feed plate with the parts in the positions theyoccupy in FIG. 2.

Referring to FIGS. 1 and 2, the stapler has a body 20 on or within whichthe operating parts of the stapler are mounted or supported. Areciprocating plunger 21, suit ably vertically guided and supported inthe body and powered by any conventional means such as a spring orpneumatic piston (not shown), furnishes the power to move a stapledriver blade 22 which is slidably mounted in ways 23 which are fixedwithin the stapler head. The staple driver 22 is guided precisely by aguiding throat or channel 24 which also serves to guide a staple as itis being driven.

The guide throat has an open end 26' through which a staple will bedriven and against which an article to be stapled may be placed. In theform of stapler shown in FIG. 1 a pair of swinging clincher arms 27 areprovided which are suitably connected and driven along with the stapledriver so that the ends of an emerging staple will be bent over orclinched at the proper time. These clinchers may be of the characterdisclosed in Patent 2,899,679, issued August 18, 1959, to H. G. Allen.Obviously if the stapler is to be used to tack, the clincher arms arenot necessary. Also, other types of staple clinching arrangements areknown in the art and the present invention does not relate to thisfeature of the apparatus. a

With the form of staple being used, which as stated above may be likethat shown in the Peterssen patent, the staplesare supplied to themachine in an unformed or partly formed state. As shown in FIG. 6, aseries of the generally straight staple blanks 28 are laterallyinterconnected by a flexible connecting web adhered under or otherwisejoining their crown portions 29 so that the resulting strip of thesestaple blanks inay be rolled, folded or otherwise compactly stored.'I'his meansthat each staple before it is used must first be formed intoa gen- 1 erally inverted U-shape having the central cross bar or crownportion 29 and depending leg portions 30. As shown in FIG. 6 the formedlegs 30 may not at first be entirely straight but when the staple isseparated from the web and finally driven, the sides of the guide throator channel 24 will accomplish the final straightening if necessary. Thisis done by means of tapering side walls 31 on the guide throat leadingto the open end 26.

Carried by the driver is a pair of former arms 32 with tapered orrounded ends which engage over the leg portions 30 of a staple blank andbend them downwardly from the crown portion 29 when the crown poltion isresting upon an anvil 33.

In the form shown in FIG. 7, the driver 22 together with the formingarms 32 may all be made from a single piece of sheet metal suitablyfolded or bent upon itself, while the guide channel 24 with its taperedside walls 31 may be made from pieces of sheet metal of the proper shapesecured together in any convenient manner. This is an economical type ofconstruction particularly useful in a light duty stapler.

It will be noted that the formers 32 are located immediately adjacentone face of the driver blade 22, which may be called the front face ofthe driver. Therefore, because the adjoining edge 34 of the anvil isspaced approximately the thickness of a staple away from the face of theguiding channel 24, when the driver blade moves downwardly in the guidechannel and passes the edge of the anvil a staple blank which has beenmoved beyond the anvil edge into the guide channel will be struck by thedriver and sheared off from the next adjacent blank in the series.Shortly after the driver has separated a staple from the row of blanks,the formers 32 which move with the driver will then shape the followingstaple over the sides of the anvil.

Although the staple driving and forming elements are here shown fastenedtogether and operated by a single plunger, obviously they can be made asseparate pieces operated by discrete mechanisms, especially if eitherthe forming operation or driving operation in a particular staplerrequires extra power or an extremely precise degree of movement.

The present invention is concerned primarily with feeding the strip ofstaple blanks at the proper times and in the proper amounts so that asone staple is being driven, another is being formed and upon return ofthe driver, the strip of interconnected staple blanks will be advancedone step to present the formed staple under the driver in its nextstroke. The principal instrumentality for this purpose is the feed plate36 shown best in its entirety in FIG. 4. Because of its peculiar actionthis plate may be called a wobble plate. It is mounted loosely under theshearing edge 34 of the anvil 33 and is resiliently biased as by springs37 toward the guiding throat or channel 24.

The structure of this plate can best be described in connection with itsaction during stapling operations. Assume that a staple has previouslybeen formed at the leading edge of the strip of staple blanks. A formedstaple is pressed toward and into the guide throat 24 by the springs 37acting on the plate 36 as shown in FIG. 2. When the plunger is actuatedto move the driver 22 downwardly the driver blade will first shear offthe formed staple as shown in FIG. 8 and start moving it downwardly inthe guiding channel. The parts, including the driver blade and the sidewalls 31 of the channel 24 are so dimensioned that the wobble plate 36is free to press the sheared staple against the face of channel 24 andhold the staple frictionally in the guiding throat to prevent itsdropping freely or tilting before the legs 30 on the staple are engagedby the tapered side wall portions 31. When once the staple has enteredthe tapered portion of the channel or guiding throat the slight spreadof the legs will insure frictional engagement with side walls of thechannel so that frictional control by the wobble plate is no longernecessary.

As the driver and former elements continue in their downward movementthe staple forming arms 32 will then engage the ends of the nextunformed staple as shown in FIG. 9 and start to form that staple, thecrown portion of the staple being supported by anvil 33. As the legs arebent downwardly and as the forming fllTIlIS pass the sides of the anvil,beveled faces 38 on the plate will be engaged by the staple legs and camthe top of the wobble plate rearwardly, tilting the plate. Furtherdownward movement of the forming arms and staple legs against the frontof the plate will straighten the latter as shown in FIG. while thedriver completes its stroke and the driven staple is clinched.

As the driver is again raised it will finally reach the position shownin FIG. 11 when its edge is opposite the crown portion of the formedstaple and above the wobble plate 36. At this point in the operation,projecting arms or extensions 39 on the plate being engaged behind theformed legs 30 on the leading staple in the strip of blanks, thepressure exerted by plate 36 tilts the tips of the legs of this stapletoward the guiding throat, all as shown in FIG. 11. As soon as thedriver passes the top margin of the strip of staples in its upwardstroke, the spring pressure on the plate will snap or push the first orlead staple against the opposing face of channel 24, pulling theattached strip of staples forwardly with it into the position of FIG. 2with the formed staple ready for the next driving stroke.

The plate is loosely held in a cavity 40 in the anvil 33, beingrestrained from excess movement at its top by a lug 41 on the plateengaging behind a shoulder 42 on the anvil. The bottom of the platerests on the bottom wall 43 of the cavity 40 and is suitably looselyrestrained as by a screw 44 the head of which is engaged in a segmentalcountersink 46 in the face of the plate.

The springs 37 bear against the plate 36 somewhat above its midpoint,considered from top to bottom, so that the desired tilting or wobbleaction of the plate is obtained as explained above.

In order to prevent the strip of staple blanks from retreating after astaple has been sheared off by the driver and before the staple formerengages the following staple blank, a top guide plate or brake 47 issuitably mounted in the body of the stapler, extending over the stapleblanks which are on the anvil 33 and over some of those on the guidingsaddle 48 leading to the anvil. This plate applies pressure or drag tothe strip of staple blanks on the saddle and anvil and is itself looselyguided by pins 49 on the stapler body extending through slots in theupturned ears 50 of this pressure plate 47. Another ear 51 may be guidedsimilarly with respect to the frame, and pressure on the plate 47 may beapplied through a plunger 52 mounted directly above the plate 47. If aconstant frictional drag is satisfactory, this may be applied by aspring (not shown) bearing against the plunger 52. If a more positiveholding of the plate 47 is desired, this may be accomplished throughknown pneumatic mechanisms arranged to push the plunger 52 against theplate 47 during the proper period in the stapling cycle, that is, fromthe time the driver shears off a formed staple until the former startsworking on the first staple blank (FIG. 9). Pneumatic actuation of theplunger 52 should also be arranged during the return stroke of thedriver and former elements until just before the parts reach therelative positions of FIG. :11 in order to urge plate 47 against thestaple blanks to prevent the returning driver and former from liftingthe staple strip off the anvil and guiding saddle. At this point anypressure on the plate 47 should be released so that the wobble plate 36may be able to pull the formed staple forward and feed the strip ofstaple blanks attached to it.

Summarizing the action of the mechanism of this invention, with theparts shown in the position of FIGS. 2 and 12, a formed staple ispressed by the action of the springs 37 on the plate 36 into the guidethroat 24. As the driver blade 22 descends, it will shear off the formedstaple at the shearing edge 34 of the anvil 33 and start driving thestaple downwardly in the guiding throat or channel. The pressure plate36 will prevent the staple being driven from shifting or canting untilthe formed legs 30 of the staple engage with the tapered walls 31 on thesides of the guiding channel. At this point the staple will be held andguided by the sides of the channel and by the end of the descendingdriver blade 22.

Soon after the driver has sheared off the first staple, the stapleforming arms 32 will engage the next staple blank which is initssubstantially flat form, and force the leg portions 30 over the sides ofthe anvil, the crown portion 29 of the staple blank being supported bythe top of the anvil 33-. As the legs of this staple are being formedover the anvil they will be forced in front of the pressure plate 36 byriding on the beveled faces 38 of the plate until the plate occupies thetilted position shown in FIG. 9. Further movement of the former arms andof the legs of the staple being formed will straighten the pressureplate vertically so that it will occupy the position shown in FIG. 10.Driving of the previously formed staple will be completed with the plate36 in this position, the newly formed staple being in front of it.

When the driver and former start their return stroke the former willfirst release itself from the legs of the formed staple and the driverblade will wipe against the front edge or face of the formed staple,tending to lift it away from the anvil. However, the pressure on topguide plate 47 will oppose this tendency and hold the formed staple andthe connected strip of blanks in proper position. When the edge of thedriver plate nears the upper edge of the crown on the leading (formed)staple blank, the springs behind the pressure plate will push theextensions 39 against the legs of the staple and tilt them forward intothe guide throat as shown in FIG. 11. As soon as the edge of the driverleaves the top edge of the staple, the springs will push the plateforwardly, moving the formed staple entirely into the guiding throat,ready for'the next driving stroke of the stapler, and thus feeding thestrip of staple blanks to the position of FIGS. 2 and 12 again.

Terms like above, below, top, vertical, forward and such, are used toindicate relative position or direction only, and are not intended todefine absolute orientation because stapling machines, instead of beingin the attitudes here illustrated, are often' inverted in use or placedagainst a vertical or slanted surface. With this in mind andcontemplating that various modifications, adaptations or substitutionsmay be made without departing from the spirit or scope of the conceptsinvolved, what is claimed is:

1. In a stapler of the character in which a seriesof relatively straightelongated laterally interconnected unforrned staple elements ispresented to a former which forms the first element of the series intoan inverted U-shape and then to adriver which drives the formed stapleelement, that improvement which comprises an anvil member for supportingthe first fiat staple element in the series, said anvil having a frontshearing edge and staple forming side surfaces thereon, a feed plateunder the anvil spring-pressed in a direction toward the searing edge ofthe anvil, staple formers movable to engage end portions of the firstflat staple element in the series and cooperating with the forming sidesurfaces of the anvil to form said first staple element into an invertedU-shape having a central crown portion and depending leg portions,beveled edges on said feed plate, the legs of the staple as it is beingformed bearing against said beveled edges and tilting the plate againstits spring pressure to a position away from the front shearing edge oftheanvil and in back of the staple legs, pusher surfaces on said feedplate engageable behind the formed legs of the staple, a guide channelin front of the feed plate and spaced from the front shearing edge ofthe anvil, a staple driver movable in said guide channel and cooperatingwith the front shearing edge of the anvil to shear the formed staplefrom the series and then to drive the formed staple in the guidechannel, the spring pressure of the feed plate frictionally holding thestaple in the guide channel during driving, return of the staple driverpermitting the pusher surfaces on the plate to engage actively behindthe staple legs whereby the spring pressure of the plate will push theformed staple toward and into the guide channel forward over theshearing edge of the anvil and pull the series of laterallyinterconnected unformed staples with it and the next formed staple willbe in the guide channel in a position ready to be driven.

2. Driving, forming and feeding mechanism fora strip of generallystraight staple blanks attached to one another along their side edgesand each blank intended before being driven to be formed into a staplehaving a central cross bar and depending leg portions, said mechanismcomprising a saddle for carrying and supporting said strip of blanks, ananvil at the end of said saddleadapted to support the cross bar of astaple blank, a guide throat spaced beyond said anvil, a driver blademovable in said guide throat between a position above the anvil where aformed staple may be fed into said guide throat and a position below theanvil where said blade may drive a formed staple in said guide throat,said blade as it passes the anvil in its movement from above the anvilto below the anvil acting to shear the end staple from said strip,staple forming shoulders carried by said driver blade and movabletherewith on either side of said anvil to form the legs on a singlestaple just after the preceding formed staple is sheared from the strip,a loosely mounted feeding plate below said anvil, a spring biasing saidplate toward said guide throat, portions on said plate engageable withlegs formed on a staple whereby said spring will urge said plate andformed staple toward and into said guide throat when said driver bladeis above said anvil, thus feeding the strip of interconnected blanks,and means frictionally holding said strip on said saddle during theperiod after the driver blade has sheared a formed staple from the stripand before the forming shoulders have produced legs engageable by theplate.

3. In an implement for forming and driving staples which are supplied inthe shape of a flexible belt of interconnected elongated staple blankseach extending transversely of the belt, said blanks each having acentral crown portion and leg portions adapted to be formed downwardlyfrom the ends of the crown portion before being driven, a saddle forguiding and supporting said belt of blanks including an anvil supportingan end of said belt at the crown portions of the staples thereof, saidanvil having a front shearing edge and side staple-forming surfaces, aguide channel with a wall spaced in front of the anvil shearing edge, aformer for shaping the leg portions of a single staple blank downwardlyover the side surfaces of the anvil, a feeder element engageable behindthe legs of a staple as they are being formed, a spring-urging saidfeeder element forwardly to advance said formed staple by its legstoward and against said guide channel wall, said belt of interconnectedblanks also advancing accordingly, a driver movable in said guidechannel for shearing a formed staple from said belt at the anvilshearing edge when a formed staple is advanced to said guide channelwall and for driving the staple thereafter in the guide channel, saidspring-urged feeder element, frictionally holding said formed andsheared staple in said guide channel as it is being driven, and meansfrictionally restraining movement of said belt with respect to saidanvil.

4. In a stapler of the character in which a series of relativelystraight elongated laterally interconnected unformed staple elements isformed and driven, that improvement which comprises a stationary memberfor supporting the first flat staple element in the series, saidstationary member having a front shearing edge and staple forming sidesurfaces thereon, a guide channel in front of the front shearing edge ofthe stationary member, a feed plate under the shearing edgespring-pressed in a direction toward said guide channel, a pair ofmovable staple formers engageable with portions of the first flat stapleelement in the series and cooperating with the forming side surfaces ofthe stationary member to form said first staple element into an invertedU-shape having a central crown portion and depending leg portions,beveled top edges on the ends of said feed plate, the legs of the stapleas it is being formed bearing against said beveled edges to tilt theplate against its spring pressure to aposition away from the frontshearing edge of the stationary member and in back of the staple legs,said feed plate having projecting arms engageable behind the formed legsof the staple, a reciprocable staple driver movable past the frontshearing edge to shear the formed staple in said guide channel from theseries and then to drive the formed staple in the guide channel whilesaid staple is frictionally held in the guide channel, return of thestaple driver permitting the spring-pressed plate to push the formedstaple toward and into the guide channel and pull the series oflaterally interconnected unformed staples with it.

5. Driving, forming and feeding mechanism for a strip of staple blanksattached to one another along a portion of their side edges and eachblank intended before being driven to be formed into a staple having acentral cross bar and depending leg portions, said mechanism comprisinga saddle for carrying and supporting said strip of blanks, an anvil atthe end of said saddle adapted to support the cross bar of a stapleblank, a guide throat spaced beyond said anvil, a driver blade movablein said guide throat between a position above the anvil where a formedstaple will be fed into said guide throat and a position below the anvilwhere said blade will drive a formed staple in said guide throat, saidblade as it passes the anvil in its movement from above the anvil tobelow the anvil acting to shear the end staple from said strip, stapleforming shoulders carried by said driver blade and movable therewith toform the legs on a single staple over said anvil, a loosely mountedfeeding plate below said anvil, a spring biasing said plate toward saidguide throat, portions on said plate engageable with legs formed on astaple whereby said spring will urge said plate and formed staple towardand into said guide throat when said driver blade is above said anvil,thus feeding the strip of interconnected blanks.

6. In an implement for forming and driving staples which are supplied inthe shape of a flexible belt of interconnected elongated staple blankseach extending transversely of the belt, said blanks each having acentral crown portion and leg portions adapted to be formed downwardlyfrom the ends of the crown portion before being driven, a saddle forguiding and supporting said belt of blanks including an anvil supportingan end of said belt at the crown portions of the staples thereof, saidanvil having a front shearing edge and staple-forming surfaces thereon,a guide channel with a Wall spaced in front of the anvil shearing edge,a former for shaping the leg portions of a single staple blankdownwardly over the staple-forming surfaces of the anvil, a feederelement engageable behind the legs of a staple as they are being formed,a spring acting on said feeder element advancing said formed staple byits legs toward and against said guide channel wall, said belt ofinterconnected blanks also advancing accordingly, a driver for shearinga formed staple from said belt at the anvil shearing edge when a formedstaple is advanced to said guide channel wall and for driving the staplethereafter in the guide channel, and said feeder element including meansfrictionally holding said formed and sheared staple in said guidechannel as it is being driven.

7. In an implement for forming and driving staples which are supplied inthe shape of a belt of interconnected elongated staple blanks eachextending transversely of the belt, said blanks each having a centralcrown portion and leg portions adapted to be formed downwardly from theends of the crown portion before being driven, a saddle for guiding andsupporting said belt of blanks including an anvil supporting an end ofsaid belt at the crown portions of staples thereof, said anvil having afront edge, a guide channel spaced in front of the anvil front edge,staple forming means for shaping the leg portions of a single stapleblank downwardly from its crown portion, a feeder element engageablebehind the legs of a staple as they are being formed, a spring urgingsaid feeder element to advance said formed staple by its legs toward andinto said guide channel, said belt of interconnected blanks alsoadvancing accordingly, a driver engaging a formed staple in said guidechannel for driving the staple and means frictionally restrainingmovement of said belt with respect to said anvil and saddle except whenadvanced by said feeder element.

8. In an implement for forming and driving staples which are supplied inthe shape of a belt of centrally interconnected elongated staple blankseach extending transversely of the belt, said blanks each having acentral portion and leg portions adapted to be formed downwardly fromthe ends of the central portion before being driven, an anvil forguiding and supporting an end of said belt at the central portions ofthe staples thereof, said anvil having a front edge, a staple drivingchannel spaced in front of the anvil front edge, staple forming meansfor shaping the leg portions of a staple blank downwardly from itscentral portion, a feeder element engageable behind the legs of a formedstaple, a spring urging said feeder element to advance said formedstaple by its legs toward and into said staple driving channel, saidbelt of interconnected blanks also advancing accordingly, and a driverfor engaging and driving a formed staple in said staple driving channel.

9. In a stapler using a continuous strip of staple blanks, each blankextending transversely of the strip and being interconnected withadjacent blanks, the combination comprising forming means for forming anend blank of the strip into a U-shaped staple, and feeding mechanism foradvancing the strip of blanks to said forming means including a movableelement engageable behind the legs of the end blank while it is beingformed and means for urging said element forwardly to advance saidformed blank beyond said forming means and to advance the followingblank to said forming means, the remainder of said strip advancingaccordingly.

10. A stapler as claimed in claim 9 comprising in addition driving meansfor driving said formed staple, said driving means being disposedadjacent to said forming means at the side thereof opposite to saidfeeding mechanism, and in which said feeding mechanism advances saidformed blank to said driving means.

11. A stapler as claimed in claim 9 comprising in addition driving meansfor driving said formed staple, said driving means being connected tothe forming means at the side thereof opposite to said feeding mechanismfor movement of said driving means together with said forming means, andin which said feeding mechanism advances said formed staple blank tosaid driving means.

,No references cited.

